When an amputation occurs or a child is born with a birth defect, the person is sometimes fitted with a prosthetic device that replaces a missing limb or other part of the body. These devices are commonly referred to as prosthesis. They are usually very expensive and come in a variety of shapes and sizes along with differing features. Typical costs associated with designing and producing a prosthetic device exceeds ten thousand U.S. dollars.
In order to better understand the invention at hand, it is necessary to understand the language used when describing certain parts of prosthetic devices.
A socket is the part of the prosthesis that comes in contact with the residual limb. Since a prosthetic device is personalized to a single residual limb, the socket is shaped to receive only a particular residual limb having a certain shape and size. That is to say, most prosthetic devices are produced for a single user and are therefore not mass produced.
Straps or a suspension lock is the portion of the prosthesis that fastens the prosthesis to the residual limb. The suspension lock may include a gel liner, a lock rod and a locking device such as a socket lock. Typically, the locking device is located in the shank of a leg prosthesis.
A lock rod is a pin or stud affixed at an end of the residual limb usually by a gel liner. The lock rod is inserted into a locking device for holding the prosthetic device onto the residual limb. It also provides a means for transmitting axial tension from the distal end wall of a gel liner through a locking mechanism and into the shank portion of the prosthetic device.
A socket lock includes a receptacle and a locking mechanism located below the socket for holding the prosthesis in place. Typically, the socket lock comprises a device that accepts the lock rod and secures it into place. A release allows the user to disengage the locking mechanism such that the prosthetic device can be removed from the residual limb.
A gel liner is a nylon sock for receiving a residual limb. The gel liner may include an integrated end fitting for accepting a lock rod or pin. It may vary in thickness throughout.
A shank is the part of the prosthesis between the knee and foot in a leg prosthesis. It ordinarily comprises metal pipe covered with foam or a hard, hollow tube.
A prosthetist measures or profiles the distal end of the residual limb to create a socket for the prosthesis. Modern advancements now allow many manufacturers to measure an end of the residual limb through the use of laser or other measuring devices.
Over time, many amputees experience shrinking of the residual limb due to reduced swelling and blood flow or muscle atrophy. This causes an inordinate amount of play between the edges of the socket and the residual limb which tends to lead to problems such as blistering or sores being created on the residual limb. To counter these problems, an amputee typically has a new prosthetic device designed and manufactured.